This invention is related generally to portable power tools, and in particular to a battery-powered torque wrench.
There are many tools available for providing a force (torque) that acts to drive a rotary load. Torque is required in a variety of applications such as turning a winch on a sailboat, a jack for lifting a car or truck, a trailer winch, a high torque drill bit, a high torque impact wrench and the like. Conventional heavy duty, high torque power drive tools are energized from a fixed power source, either electrical or mechanical, which limits portability. For example, some power tools use an extension power cable for connection to a remote electrical power outlet. In other power tools, heavy internal combustion engines are utilized. But those tools cannot be easily moved or handled. The connection to a fixed electrical power supply limits the useful range, and an internal combustion engine adds considerable weight and size to the power tool.
Such conventional power tools cannot be used in all applications. For example, in sailboats the sails are raised manually by a mechanical winch. The raising and lowering of the sails can be very tedious and laborious work. However, electrically powered winches are not practical in such applications that require an electrical cable to supply operating power from a compatible source. Motorized winches are much too large, heavy and expensive. Additionally, the size of a powered winch must be minimized for use within the limited deck space available on a sailboat.
In another example, a power tool may be needed when tightening and loosening nuts and bolts on heavy equipment and machinery. Conventional power tools are much too large or must be tethered to electrical power outlets, making them impractical for use in remote locations.
A conventional power tool is disclosed in U.S. Pat. No. 5,386,970 to Trant. According to Trant, a power handle for rotating the capstan of a manual winch includes a housing, a motor, a star stub for engaging and rotating the capstan relative to the housing, and a gear reduction unit for connecting the motor to the star stub. Additionally, the handle is connected by an electrical power cable to an electrical power supply. Trant does not disclose a completely portable power drive device since the Trant power tool must be energized from a remote power source through an electrical power cable.
Some conventional power tools utilize a rechargeable battery, for example cordless drills, screwdrivers and saws. However, those tools lack sufficient power to handle high torque, heavy duty power drive applications. Consequently, there is a continuing interest in providing a battery operated, high torque, portable power tool for use in confined areas or at a remote location where an electrical power supply is not readily available.